'15 DF300 with SMG4 communication issues

[DrumStick]

Just installed a new to me 2015 DF300AP with an SMG4 gauge. Location is US if that matters. A few things I am experiencing:
Trim does not work or calibrate on the gauge
The gauge is linked to my NMEA2000 network and shows up on my Garmin 942xs however the only gauge that works is the tachometer.

Is this normal for the older 300's interface with the SMG4, or is there something to check to make sure I am hooked up correctly?

[Murray]

https://www.suzukioutboardforum.com/...a2000-networks

Some reading material

[DrumStick]

I did read through that thread and unfortunately no help. The NMEA backbone is hooked up correctly, and the gauge itself works as it should (with exception to showing engine trim).

According to Suzuki the SMG4 gauge's NMEA2000 connection should output engine data and accept GPS data. It is accepting GPS and outputting only RPM data.

[Moonlighter]

Have you been into the Initial Settings menu, sensors, trim?

How do you know that SMG4 is only outputting rpm? The issue could be that the Garmin is only displaying rpm from all the data available on the network….

[DrumStick]

Yes it was all set up by the book. I knew only RPM by changing displays to all kinds of other available options. The problem turned out to be within the NMEA2000 backbone power. I used a power isolator for the SMG4 and suzuki harness NMEA2000 power to the rest of the items in the backbone (Garmin 942xs, Fusion radio, NMEA2000 Power, Garmin 19x GPS Puck) - once powered up information showed correctly.

[Buckkoo]

2020DF250SS connected to SMG4 and a pair of Garmins. Since adding a second Garmin, I have lost engine trim on both Garmins and the SMG4.

Is a power insulator something I should try?

Also, is there a list somewhere of what engine data the Suzuki should be passing to the NEMA2000 network? Some of the Garmin gauges don't seem to be receiving data

[Moonlighter]

The following info is sent to the network from the SMG

RPM, alternator voltage, engine temperature, engine hours, trim, fuel flow rate.

The Garmin itself will calculate fuel used based on fuel flow, and you need to set up the Garmin to tell it how many engines and fuel capacity.

Ive seen several reports of problems caused when some Garmin units are connected to SMG4. Suggest that for now, you disconnect the second unit that caused the problems to happen.

[Buckkoo]

Hmmm, I was hoping for a grounding issue or similar.

I agree that its worth removing the 2nd Garmin, which I installed to display engine data, to see if Trim returns.

It is difficult to understand how adding a 2nd Garmin would prevent Trim from showing up on the SMG as that is a pre-NEMA connection.

As far as NEMA goes, it has been interesting and disappointing speaking with Garmin support as you learn that NEMA support does not mean full NEMA support for every function across devices, but rather a select subset of data is shared depending on the device.